Installation Guide

32
DECKING
Sleeper Deck Systems
A sleeper system is a buffer between a solid surface
and Trex
®
decking. Drainage, access, and airflow are
critical. Water must be able to flow through and away
from the deck. For repairs and removal of debris, joist
system access is necessary. Good airflow will keep the
decking dry and in good condition.
Trex, when used with a sleeper system, must be
supported below its entire length and if used in a
roofing application, the supports must run the direction
of the pitch of the roof to facilitate proper drainage. In
addition, sleeper joists must be attached to the roof
structure in a manner that stabilizes the deck frame.
Failure to do so may result in a poor structure which will
compromise deck performance.
In areas of application where a sleeper system is
required that would not be susceptible to excessive
debris buildup (examples would include covered areas
such as balconies, porches, etc.), a minimum height
of 1-1/2" (3.8 cm) for pressure-treated joists as well as
a minimum 1/4" (0.6 cm) gap between Trex decking
would be acceptable. These areas would still have to
be designed to allow for proper drainage and hidden
fasteners would be acceptable. However, if access to
the structure under the decking is required, it would be
recommended to use either the Universal Fastener
(plastic) or 2” (5.1 cm) composite decking screws. A
1 /4" (0.6 cm) to 1/2" (1.3 cm) gap is still required when
abutting walls or other fixed objects.
In all other areas where there could be excessive
water buildup along with debris buildup, Trex would
recommend a minimum height of 3-1/2" (8.9 cm) for
pressure-treated joists, as well as a gap of 3/8"
(1 cm). For this application, hidden fasteners would not
be recommended and standard 3" (7.6 cm) composite
screws would be used.
ALWAYS consult your local building code authority for
proper details on roof and railing installation to the roof
structure if required.
ROOFTOP AND SLEEPER DECK SYSTEMS
ROOFTOP DECK TIPS
» If you want to access the roof, you must build
the Trex deck in removable sections or with
removable fasteners.
» You must attach the sleeper joists to the roof
structure so that they stabilize the deck frame.
Failure to do so may result in a poor structure
which will compromise deck performance.